- Ligand-controlled cobalt-catalyzed remote hydroboration and alkene isomerization of allylic siloxanes
-
The Co-catalyzed remote hydroboration and alkene isomerization of allylic siloxanes were realized by a ligand-controlled strategy. The remote hydroboration with dcype provided borylethers, while xantphos favored the formation of silyl enol ethers.
- Huang, Jiaxin,Li, Jie,Yang, Wen,Zhang, Kezhuo,Zhao, Pei,Zhao, Wanxiang
-
supporting information
p. 302 - 305
(2022/01/03)
-
- Nickel-catalyzed reductive defluorination of iodo allylic: Gem -difluorides: Allenyl monofluoride synthesis
-
As a potential fluorinated synthon, there have been only limited reports on fluorinated allene synthesis and applications due to concerns about their stability. Here, we developed a nickel-catalyzed reductive defluorination of iodo allyl gem-difluorides to afford allenyl monofluorides under mild conditions with good functional group tolerance, which were easily converted to other C-F bond compounds, such as alkyl and alkenyl fluorides. Preliminary mechanistic studies suggested that monofluoroallenes were yielded by β-F elimination of the alkenyl C-Ni intermediates from the oxidative addition of C-I bonds to a nickel(0) catalyst, while zinc regenerates the catalyst and closes the catalytic cycle.
- You, Yiming,Wu, Jiayue,Yang, Lixin,Wu, Tao
-
supporting information
p. 1970 - 1973
(2022/02/19)
-
- Synthesis of rac-ɑ-aryl propionaldehydes via branched-selective hydroformylation of terminal arylalkenes using water-soluble Rh-PNP catalyst
-
This work detailed the preparation of a class of water-soluble PNP ligands that differed by the nature of the substitute on phenyl ring of ligands. These ligands were incorporated into water-soluble rhodium-PNP complex catalysts that were used to regioselective hydroformylation of a series of terminal arylalkenes, providing efficient access to rac-α-aryl propionaldehydes in good to excellent yield (up to 97%) and branched-regioselectivity (up to 40:1 b/l ratio). Furthermore, gram-scale and diverse synthetic transformation demonstrated synthetic application of this methodology for non-steroidal antiinflammatory drugs.
- Chen, Fen-Er,Gao, Peng,Ke, Miaolin,Liang, Guanfeng,Ru, Tong
-
-
- Multicatalytic approach to one-pot stereoselective synthesis of secondary benzylic alcohols
-
One-pot procedures bear the potential to rapidly build up molecular complexity without isolation and purification of consecutive intermediates. Here, we report multicatalytic protocols that convert alkenes, unsaturated aliphatic alcohols, and aryl boronic acids into secondary benzylic alcohols with high stereoselectivities (typically >95:5 er) under sequential catalysis that integrates alkene cross-metathesis, isomerization, and nucleophilic addition. Prochiral allylic alcohols can be converted to any stereoisomer of the product with high stereoselectivity (>98:2 er, >20:1 dr).
- Casnati, Alessandra,Lichosyt, Dawid,Lainer, Bruno,Veth, Lukas,Dydio, Pawe?
-
supporting information
p. 3502 - 3506
(2021/05/10)
-
- Access to Trisubstituted Fluoroalkenes by Ruthenium-Catalyzed Cross-Metathesis
-
Although the olefin metathesis reaction is a well-known and powerful strategy to get alkenes, this reaction remained highly challenging with fluororalkenes, especially the Cross-Metathesis (CM) process. Our thought was to find an easy accessible, convenient, reactive and post-functionalizable source of fluoroalkene, that we found as the methyl 2-fluoroacrylate. We reported herein the efficient ruthenium-catalyzed CM reaction of various terminal and internal alkenes with methyl 2-fluoroacrylate giving access, for the first time, to trisubstituted fluoroalkenes stereoselectively. Unprecedent TON for CM involving fluoroalkene, up to 175, have been obtained and the reaction proved to be tolerant and effective with a large range of olefin partners giving fair to high yields in metathesis products. (Figure presented.).
- Nouaille, Augustin,Pannecoucke, Xavier,Poisson, Thomas,Couve-Bonnaire, Samuel
-
p. 2140 - 2147
(2021/03/06)
-
- Transfer hydrogenations catalyzed by streptavidin-hosted secondary amine organocatalysts
-
Here, the streptavidin-biotin technology was applied to enable organocatalytic transfer hydrogenation. By introducing a biotin-tethered pyrrolidine (1) to the tetrameric streptavidin (T-Sav), the resulting hybrid catalyst was able to mediate hydride transfer from dihydro-benzylnicotinamide (BNAH) to α,β-unsaturated aldehydes. Hydrogenation of cinnamaldehyde and some of its aryl-substituted analogues was found to be nearly quantitative. Kinetic measurements revealed that the T-Sav:1 assembly possesses enzyme-like behavior, whereas isotope effect analysis, performed by QM/MM simulations, illustrated that the step of hydride transfer is at least partially rate-limiting. These results have proven the concept thatT-Savcan be used to host secondary amine-catalyzed transfer hydrogenations.
- Santi, Nicolò,Morrill, Louis C.,?widerek, Katarzyna,Moliner, Vicent,Luk, Louis Y. P.
-
supporting information
p. 1919 - 1922
(2021/03/02)
-
- Radical Carbonyl Propargylation by Dual Catalysis
-
Carbonyl propargylation has been established as a valuable tool in the realm of carbon–carbon bond forming reactions. The 1,3-enyne moiety has been recognized as an alternative pronucleophile in the above transformation through an ionic mechanism. Herein, we report for the first time, the radical carbonyl propargylation through dual chromium/photoredox catalysis. A library of valuable homopropargylic alcohols bearing all-carbon quaternary centers could be obtained by a catalytic radical three-component coupling of 1,3-enynes, aldehydes and suitable radical precursors (41 examples). This redox-neutral multi-component reaction occurs under very mild conditions and shows high functional group tolerance. Remarkably, bench-stable, non-toxic, and inexpensive CrCl3 could be employed as a chromium source. Preliminary mechanistic investigations suggest a radical-polar crossover mechanism, which offers a complementary and novel approach towards the preparation of valuable synthetic architectures from simple chemicals.
- Huang, Huan-Ming,Bellotti, Peter,Daniliuc, Constantin G.,Glorius, Frank
-
supporting information
p. 2464 - 2471
(2020/12/07)
-
- Insight into decomposition of formic acid to syngas required for Rh-catalyzed hydroformylation of olefins
-
Formic acid (FA) is one kind of important bulk chemicals, which is recognized as a sustainable and eco-friendly energy carrier to transport H2 via dehydrogenation or CO via decarbonylation. Expectantly, FA upon decomposition into H2 and CO could be used as the syngas alternative for hydroformylation. In this paper, the behaviors of FA to release H2 as well as CO following the distinct pathways were carefully investigated for the first time, and then established a new hydroformylation protocol free of syngas. It was found that the atmospheric hydroformylation of olefins with formic acid (FA) as syngas alternative was smoothly fulfilled over Xantphos (L1) modified Rh-catalyst under mild conditions (80 °C, Rh concentration 1 mol %, 14 h), resulting in >90% conversion of the olefins along with the high selectivity to the target aldehydes (>93%). By using FA as syngas source, the side-reaction of olefin-hydrogenation was greatly depressed. The in situ FT-IR and the high-pressure 1H NMR spectroscopic analyses were applied to reveal how FA behaves dually as CO surrogate and hydrogen source over L1-Rh(acac)(CO)2 catalytic system, based on which the deeply insight into the catalytic mechanism of hydroformylation of olefins with FA as syngas alternative was offered.
- Liu, Lei,Chen, Xiao-Chao,Yang, Shu-Qing,Yao, Yin-Qing,Lu, Yong,Liu, Ye
-
p. 406 - 415
(2020/12/07)
-
- Binuclear Pd(I)-Pd(I) Catalysis Assisted by Iodide Ligands for Selective Hydroformylation of Alkenes and Alkynes
-
Since its discovery in 1938, hydroformylation has been thoroughly investigated and broadly applied in industry (>107 metric ton yearly). However, the ability to precisely control its regioselectivity with well-established Rh- or Co-catalysts has thus far proven elusive, thereby limiting access to many synthetically valuable aldehydes. Pd-catalysts represent an appealing alternative, yet their use remains sparse due to undesired side-processes. Here, we report a highly selective and exceptionally active catalyst system that is driven by a novel activation strategy and features a unique Pd(I)-Pd(I) mechanism, involving an iodide-assisted binuclear step to release the product. This method enables β-selective hydroformylation of a large range of alkenes and alkynes, including sensitive starting materials. Its utility is demonstrated in the synthesis of antiobesity drug Rimonabant and anti-HIV agent PNU-32945. In a broader context, the new mechanistic understanding enables the development of other carbonylation reactions of high importance to chemical industry.
- Zhang, Yang,Torker, Sebastian,Sigrist, Michel,Bregovi?, Nikola,Dydio, Pawe?
-
supporting information
p. 18251 - 18265
(2020/11/02)
-
- Synthesis and inhibitory studies of phosphonic acid analogues of homophenylalanine and phenylalanine towards alanyl aminopeptidases
-
A library of novel phosphonic acid analogues of homophenylalanine and phenylalanine, containing fluorine and bromine atoms in the phenyl ring, have been synthesized. Their inhibitory properties against two important alanine aminopeptidases, of human (hAPN, CD13) and porcine (pAPN) origin, were evaluated. Enzymatic studies and comparison with literature data indicated the higher inhibitory potential of the homophenylalanine over phenylalanine derivatives towards both enzymes. Their inhibition constants were in the submicromolar range for hAPN and the micromolar range for pAPN, with 1-amino-3-(3-fluorophenyl) propylphosphonic acid (compound 15c) being one of the best low-molecular inhibitors of both enzymes. To the best of our knowledge, P1 homophenylalanine analogues are the most active inhibitors of the APN among phosphonic and phosphinic derivatives described in the literature. Therefore, they constitute interesting building blocks for the further design of chemically more complex inhibitors. Based on molecular modeling simulations and SAR (structure-activity relationship) analysis, the optimal architecture of enzyme-inhibitor complexes for hAPN and pAPN were determined.
- Wanat, Weronika,Talma, Micha?,Dziuk, B?a?ej,Kafarski, Pawe?
-
-
- Chemoselective hydrogenation of α,β-unsaturated aldehydes over Rh nanoclusters confined in a metal-organic framework
-
Selective hydrogenation of α,β-unsaturated aldehydes to achieve high selectivity towards a desirable product is still a great challenge mainly because of the complex conjugate system. Herein, Rh nanoclusters encapsulated in MIL-101 (Cr), synthesized by the double solvent method, are able to selectively hydrogenate C-C of cinnamaldehyde, an α,β-unsaturated aldehyde and achieve over 98percent selectivity with a conversion of 98percent to a saturated aldehyde under mild conditions. Fourier transform infrared spectroscopy confirms that MIL-101 acts as an aldehyde protector to suppress the reactivity of C-O, and the X-ray photoelectron spectroscopy (XPS) data indicate that the electropositive Rh, owing to the electron transfer from Rh to MIL-101, preferentially absorbs C-C rather than C-O leading to -improvement of the selectivity towards saturated aldehydes. In addition, Rh@MIL-101 can also efficiently catalyse hydrodefluorination of aryl fluorides with good stability. This work provides a basic strategy to develop other selective heterogeneous catalystsviastructural modulation for synergetic catalysis.
- Liu, Qinglin,Li, Yinle,Fan, Yanan,Su, Cheng-Yong,Li, Guangqin
-
p. 11442 - 11447
(2020/06/29)
-
- Diaza-Crown Ether-Bridged Chiral Diphosphoramidite Ligands: Synthesis and Applications in Asymmetric Catalysis
-
A small library of diaza-crown ether-bridged chiral diphosphoramidite ligands was prepared. In the rhodium-catalyzed asymmetric hydrogenation and hydroformylation reactions, these ligands exhibited distinct properties in catalytic activity and/or enantioselectivity. Hydrogenated products with opposite absolute configurations could be obtained in high yields with excellent ee values by utilizing (S,S)-L1 and (S,S)-L3, respectively. Meanwhile, the addition of alkali metal cations caused variations in catalytic outcomes, showing the supramolecular tunability of these Rh/diphosphoramidite catalytic systems.
- Luo, Yier,Ouyang, Guanghui,Tang, Yuping,He, Yan-Mei,Fan, Qing-Hua
-
p. 8176 - 8184
(2020/07/15)
-
- Transition-Metal-Free Synthesis of Electron Rich 1,3-Dienes via Base Promoted Isomerization of Propargylic Ethers
-
Herein, a novel and scalable synthesis of electron rich 1,3-dienes based on KOtBu mediated isomerization of propargylic ether derivatives was developed. This new process features easy handling reaction conditions, transition-metal-free isomerization, high isolated yields, and most of all, it could be used for modification of natural products at late stage functionalizations.
- Liu, Chunxiang,Deng, Guogang,Li, Xin,Xu, Yiren,Yu, Kaili,Chen, Wen,Zhang, Hongbin,Yang, Xiaodong
-
supporting information
p. 483 - 487
(2020/01/25)
-
- Remote Functionalization of α,β-Unsaturated Carbonyls by Multimetallic Sequential Catalysis
-
The remote functionalization of α,β-unsaturated carbonyls by an array of multimetallic sequential catalytic systems is described. The reactions are triggered by hydrometalation using [Pd-H] or [Ru-H] isomerization catalysts and driven by the formation of thermodynamically more stable 1,2-vinyl arenes. The Pd-catalyzed deconjugative isomerization was combined with a Cu-catalyzed β-borylation of the transiently generated styrenyl derivatives to deliver a range of products that would not be accessible with the use of a single catalyst. [Pd/Cu] catalytic systems were also identified for the highly enantioselective α-hydroboration and α-hydroamination of the styrenyl intermediates. Difunctionalization simultaneously at the benzylic and homobenzylic positions was achieved by combining the isomerization process with Sharpless asymmetric dihydroxylation (SAD) using [Pd/Os] or [Ru/Os] couples. Starting from a simple α,β-unsaturated ester, an isomerization/dihydroxylation/lactonization sequence gave access to a naturally occurring γ-butyrolactone in good yield, with excellent diastereo- and enantioselectivity.
- Romano, Ciro,Fiorito, Daniele,Mazet, Clément
-
supporting information
p. 16983 - 16990
(2019/10/28)
-
- Asymmetric Multifunctional Modular Organocatalysis: One-Pot Direct Strategy to Enantiopure α,β-Disubstituted γ-Butyrolactones
-
A simple and efficient approach to enantioenriched α,β-disubstituted γ-butyrolactones has been developed through multifunctional modular organocatalysis in a highly enantioselective (>99% ee) and diastereoselective (>30:1) manner following a one-pot sequential Michael-hemiacetalization-oxidation reaction. The catalytic process has great substrate compatibility, and the products have been transformed to synthetically useful molecules. The methodology has also been applied to the formal synthesis of (+)-Pilocarpine.
- Mahto, Pratibha,Rana, Nirmal K.,Shukla, Khyati,Das, Braja G.,Joshi, Harshit,Singh, Vinod K.
-
supporting information
p. 5962 - 5966
(2019/08/20)
-
- Tandem IBX-Promoted Primary Alcohol Oxidation/Opening of Intermediate β,γ-Diolcarbonate Aldehydes to (E)-γ-Hydroxy-α,β-enals
-
A tandem IBX-promoted oxidation of primary alcohol to aldehyde and opening of intermediate β,γ-diolcarbonate aldehyde to (E)-γ-hydroxy-α,β-enal has been developed. Remarkably, the carbonate opening delivered exclusively (E)-olefin and no over-oxidation of γ-hydroxy was observed. The method developed has been extended to complete the stereoselective total synthesis of both (S)- and (R)-coriolides and d-xylo- and d-arabino-C-20 guggultetrols.
- Kumari, Anupama,Gholap, Sachin P.,Fernandes, Rodney A.
-
p. 2278 - 2290
(2019/06/17)
-
- MICROCAPSULES AND PROCESSES FOR THEIR PREPARATION
-
The present invention provides microcapsules encapsulating hydrophilic or hydrophobic active agents in an inorganic shell, processes for their preparation and compositions comprising them.
- -
-
Page/Page column 28-30
(2019/06/11)
-
- Carbene-Catalyzed α-Carbon Amination of Chloroaldehydes for Enantioselective Access to Dihydroquinoxaline Derivatives
-
An NHC-catalyzed α-carbon amination of chloroaldehydes was developed. Cyclohexadiene-1,2-diimines are used as amination reagents and four-atom synthons. Our reaction affords optically enriched dihydroquinoxalines that are core structures in natural products and synthetic bioactive molecules.
- Huang, Ruoyan,Chen, Xingkuan,Mou, Chengli,Luo, Guoyong,Li, Yongjia,Li, Xiangyang,Xue, Wei,Jin, Zhichao,Chi, Yonggui Robin
-
p. 4340 - 4344
(2019/06/14)
-
- Ligand-Controlled Regiodivergent Silylation of Allylic Alcohols by Ni/Cu Catalysis for the Synthesis of Functionalized Allylsilanes
-
The first Ni/Cu-catalyzed regiodivergent synthesis of allylsilanes directly from allylic alcohols through modulating the steric and electronic properties of the ligands on the nickel catalyst has been developed. Good yields and excellent selectivity were obtained regardless of whether linear or α-branched allylic alcohols were utilized. Mechanistic studies indicate that an allyloxyboronate species is formed during the reaction, which likely serves as an activated intermediate toward the oxidative addition of the C(allyl)-O bond.
- Gan, Yi,Xu, Wei,Liu, Yuanhong
-
supporting information
p. 9652 - 9657
(2019/11/28)
-
- Access to β-Ketonitriles through Nickel-Catalyzed Carbonylative Coupling of α-Bromonitriles with Alkylzinc Reagents
-
Herein, we report a nickel-catalyzed carbonylative coupling of α-bromonitriles and alkylzinc reagents with near stoichiometric carbon monoxide to give β-ketonitriles in good yields. The reaction is catalyzed by a readily available and stable nickel(II) pincer complex. The developed protocol tolerates substrates bearing a variety of functional groups, which would be problematic or incompatible with previous synthetic methods. Additionally, we demonstrate the suitability of the method for carbon isotope labeling by the synthesis of 13C-labeled β-ketonitriles and their transformation into isotopically labeled heterocycles.
- Donslund, Aske S.,Neumann, Karoline T.,Corneliussen, Nicklas P.,Grove, Ebbe K.,Herbstritt, Domenique,Daasbjerg, Kim,Skrydstrup, Troels
-
supporting information
p. 9856 - 9860
(2019/07/09)
-
- HETEROARYL-CARBOXYLIC ACIDS AS HISTONE DEMETHYLASE INHIBITORS
-
The invention relates to heteroaryl-carboxylic acids as described herein, useful as histone demethylase inhibitors. The invention also relates to pharmaceutical compositions comprising these compounds and to their use in therapy, including e.g., in the treatment of cancer.
- -
-
Page/Page column 79
(2018/01/17)
-
- Enantioselective hydroformylation of 2- and 4-substituted styrenes with PtCl2[(R)-BINAP] + SnCl2‘in situ’ catalyst
-
Two sets of styrenes possessing various substituents either in ortho or para position were hydroformylated in the presence of ‘in situ’ catalyst formed from PtCl2[(R)-BINAP] and tin(II) chloride. The reversal of the absolute configuration of the preferred enantiomers was observed using both sets of substrates by the variation of the reaction temperature in the range of 40–100 °C. In case of the 4-substituted styrenes, the reversal temperature of the enantioselectivity shows correlation with the Hammett substituent constants, i.e., with the electron donor or electron acceptor properties of the para-substituents. This phenomenon was explained by the reversible formation of the Pt-branched alkyl intermediates, leading to the corresponding (R)- and (S)-enantiomers of 2-arylpropanals. Strong substituent effect on the regioselectivity was observed in the hydroformylation of 2-substituted styrenes: the presence of substituents characterised by larger steric parameter resulted in the highly favoured formation of the linear aldehyde. For instance, regioselectivities of 45%, 22% and 7% towards branched aldehyde were obtained with styrene, 2-fluoro- and 2-bromostyrene, respectively, at 80 °C reaction temperature. In addition to the characteristic change of regioselectivity, the reversal of absolute configuration as a function of reaction temperature was also observed.
- Pongrácz, Péter,Kollár, László
-
p. 118 - 123
(2016/10/25)
-
- Synthesis and fungicidal activity study of novel daphneolone analogs with 2,6-dimethylmorpholine
-
A series of novel daphneolone analogs was designed and synthesized on the basis of natural product 1,5-diphenyl-2-penten-1-one (I) from Stellera chamaejasme L. as lead compound, whereby 2,6-dimethylmorpholine moiety was introduced to replace 1-phenyl group. Their structures were confirmed by IR, 1H NMR, and HRMS (ESI) or elemental analysis, 13C NMR for some representative compounds. The two isomers of target compounds were separated and identified by NOESY technique and chemical method. All of the synthesized compounds have been evaluated for anti-plant pathogenic fungi activities. The results showed that some compounds exhibited moderate to good antifungal activities against tested fungi at the concentration of 50 mg/L. Among them, compound 7d, with a 4-bromine-substituted phenyl group and cis-2,6-dimethylmorpholine moiety, displayed best activity with an EC50 of 23.87 μmol/L against Valsa Mali, superior to lead compound I. In addition, preliminary structure-activity relationship analysis indicated that, between two isomers of target compounds, the antifungal activities of the isomer with cis-2,6-dimethylmorpholine were better than the trans-isomer.
- Xu, Gao-Fei,Yang, Xin-Ling,Lei, Peng,Liu, Xi-Li,Zhang, Xue-Bo,Ling, Yun
-
p. 555 - 558
(2016/04/26)
-
- Promotion effect of water on hydroformylation of styrene and its derivatives with presence of amphiphilic zwitterionic phosphines
-
Two kinds of novel zwitterionic phosphines of L1 and L2 have been synthesized in which the sulfonate groups (-SO3-) are incorporated to render them amphiphilic. Both of them are strong π-acceptor ligands in which the positive-charged imidazoliums with intensive electron-withdrawing effect are vicinal to the coordinating phosphorous atoms. The amino-group of piperidyl is additionally incorporated in L2 to make it behave as a hybrid ligand with potential hemilability. The comparison of the ligands of L1 and L2 in Rh-catalyzed hydroformylation of styrene (and its derivatives) and the effect of water on their behaviors were discussed. Without the involvement of water, the catalytic system of Rh(acac)(CO)2-L2 exhibited lower activity than that of Rh(acac)(CO)2-L1 under the same conditions. However, the dramatic promotion effect of water as a suspension was observed especially for Rh(acac)(CO)2-L2 system with TOF spurred up from 195 to 470 h-1. The corresponding in situ high pressure FT-IR spectral information showed that the presence of water in Rh(acac)(CO)2-L2 system greatly facilitated the formation and stability of the active Rh-H species (νRh-H, 2047 cm-1), which was in charge of the efficient hydroformylation of styrene and its derivatives.
- Chen, Sheng-Jie,Li, Yong-Qi,Wang, Peng,Lu, Yong,Zhao, Xiao-Li,Liu, Ye
-
p. 212 - 220
(2015/07/28)
-
- HIV INTEGRASE INHIBITORS
-
The present invention features compounds that are HIV integrase inhibitors and therefore are useful in the inhibition of HIV replication, the prevention and/or treatment of infection by HIV, and in the treatment of AIDS and/or ARC.
- -
-
-
- Accessible protocol for asymmetric hydroformylation of vinylarenes using formaldehyde
-
We report herein on an accessible protocol for the asymmetric hydroformylation of vinylarenes using formaldehyde as a substitute for syngas. The regioselectivity (branched/linear = up to 96/4) and enantioselectivity (up to 95% ee) can be attributed to the use of chiral Ph-bpe as a ligand. This journal is
- Morimoto, Tsumoru,Fujii, Tetsuji,Miyoshi, Kota,Makado, Gouki,Tanimoto, Hiroki,Nishiyama, Yasuhiro,Kakiuchi, Kiyomi
-
supporting information
p. 4632 - 4636
(2015/04/27)
-
- Dual Catalytic Activity of Palladium Doped with a Rhodium Complex in a One-pot, Four Step Process
-
The extraction of the two competing reactions from the same catalyst - a composite catalytic-complex@catalytic-metal - is reported. A Wilkinson rhodium based catalyst entrapped within metallic palladium catalyst is shown to perform both hydroformylation and hydrogenation with a ratio that depends on H2 and CO pressures. Here we demonstrate this special reactivity in a one-pot, four step sequence, which include hydroformylations of phenyl acetylenes, reduction of nitrobenzene to aniline, carbonyl-amine condensations forming imines; and imine reductions.
- Shapiro, Leora,Driess, Matthias,Avnir, David
-
p. 2033 - 2037
(2015/11/24)
-
- Scope and mechanism in palladium-catalyzed isomerizations of highly substituted allylic, homoallylic, and alkenyl alcohols
-
Herein we report the palladium-catalyzed isomerization of highly substituted allylic alcohols and alkenyl alcohols by means of a single catalytic system. The operationally simple reaction protocol is applicable to a broad range of substrates and displays a wide functional group tolerance, and the products are usually isolated in high chemical yield. Experimental and computational mechanistic investigations provide complementary and converging evidence for a chain-walking process consisting of repeated migratory insertion/β-H elimination sequences. Interestingly, the catalyst does not dissociate from the substrate in the isomerization of allylic alcohols, whereas it disengages during the isomerization of alkenyl alcohols when additional substituents are present on the alkyl chain.
- Larionov, Evgeny,Lin, Luqing,Gune, Laure,Mazet, Clment
-
supporting information
p. 16882 - 16894
(2015/01/09)
-
- Influence of the 4-substituents on the reversal of enantioselectivity in the asymmetric hydroformylation of 4-substituted styrenes with PtCl(SnCl 3)[(2 S, 4 S)-BDPP]
-
The enantioselectivity of the asymmetric hydroformylation of 4-substituted styrenes in the presence of an in situ catalyst, formed from PtCl(SnCl 3)[(2S,4S)-BDPP] and tin(II) chloride, was influenced by the reaction temperature. The preferred formation of the S and the R enantiomers of the branched aldehyde regioisomers (2a-g) was observed at low and high temperatures, respectively. The electron-donor or electron-acceptor properties of the para substituents of styrene show correlation with the changes in enantioselectivity, especially with the reversal temperature of the enantioselectivity. The reversibility of the formation of the Pt-branched alkyl intermediates, leading to the corresponding R and S enantiomers of 2-arylpropanals, depends on the Hammett constants. The electronic effect of para substituents was investigated by quantum chemical methods employing the simple olefin adducts [HPt(PH 3)2(olefin)(SnCl3)]. Excellent linear correlation was found between the para substituent constants and the electrostatic potential at nuclei of the platinum atom. Equally good correlation has been established for the other atoms as well in the coordination sphere of Pt.
- Pongracz, Peter,Papp, Tamara,Kollar, Laszlo,Kegl, Tamas
-
supporting information
p. 1389 - 1396
(2014/04/17)
-
- Easily accessible and highly tunable bisphosphine ligands for asymmetric hydroformylation of terminal and internal alkenes
-
An efficient methodology for synthesizing a small library of easily tunable and sterically bulky ligands for asymmetric hydroformylation (AHF) has been reported. Five groups of alkene substrates have been tested with excellent conversions, moderate-to-excellent regio- and enantioselectivities. Among the best result of the reported literature, application of ligand 1 c in the highly selective AHF of the challenging substrate 2,5-dihydrofuran yielded almost one isomer in up to 99 % conversion along with enantiomeric excesses (ee) of up to 92 %. Highly enantioselective AHF of dihydropyrrole substrates is achieved using the same ligand, with up to 95 % ee and up to >1:50 β-isomer/α- isomer ratio. The simpler the better! An efficient method for the easy and tunable synthesis of a series of asymmetric hydroformylation (AHF) ligands from low-cost, commercially available starting materials has been reported. These ligands can give excellent conversions and moderate to excellent regio- and enantioselectivities for a broad range of mono- and disubstituted alkenes with a low catalyst loading (substrate-to-catalyst ratios (S/C) of 1000:1 to 3000:1).
- Xu, Kun,Zheng, Xin,Wang, Zhiyong,Zhang, Xumu
-
p. 4357 - 4362
(2014/05/06)
-
- Flow Chemistry Syntheses of Styrenes, Unsymmetrical Stilbenes and Branched Aldehydes
-
Two tandem flow chemistry processes have been developed. A single palladium-catalysed Heck reaction with ethylene gas provides an efficient synthesis for functionalised styrenes. Through further elaboration the catalyst becomes multi-functional and performs a second Heck reaction providing a single continuous process for the synthesis of unsymmetrical stilbenes. In addition, the continuous, rhodium-catalysed, hydroformylation of styrene derivatives with syngas affords branched aldehydes with good selectivity. Incorporation of an in-line aqueous wash and liquid-liquid separation allowed for the ethylene Heck reaction to be telescoped into the hydroformylation step such that a single flow synthesis of branched aldehydes directly from aryl iodides was achieved. The tube-in-tube semi-permeable membrane-based gas reactor and liquid-liquid separator both play an essential role in enabling these telescoped flow processes.
- Bourne, Samuel L.,O'Brien, Matthew,Kasinathan, Sivarajan,Koos, Peter,Tolstoy, Paeivi,Hu, Dennis X.,Bates, Roderick W.,Martin, Benjamin,Schenkel, Berthold,Ley, Steven V.
-
p. 159 - 172
(2013/03/13)
-
- A natural product inspired tetrahydropyran collection yields mitosis modulators that synergistically target CSE1L and tubulin
-
A Prins cyclization between a polymerbound aldehyde and a homoallylic alcohol served as the key step in the synthesis of tetrahydropyran derivatives. A phenotypic screen led to the identification of compounds that inhibit mitosis (as seen by the accumulation of round cells with condensed DNA and membrane blebs; see picture). These compounds were termed tubulexins as they target the CSE1L protein and the vinca alkaloid binding site of tubulin.
- Voigt, Tobias,Gerding-Reimers, Claas,Tran, Tuyen Thi Ngoc,Bergmann, Sabrina,Lachance, Hugo,Sch?lermann, Beate,Brockmeyer, Andreas,Janning, Petra,Ziegler, Slava,Waldmann, Herbert
-
p. 410 - 414
(2013/02/23)
-
- HETEROCYCLIC COMPOUNDS AND METHODS FOR THEIR USE
-
The present invention relates to heterocyclic compounds useful for antagonising angiotensin II Type 2 (AT2) receptor. More particularly the invention relates to pyrrolidine and azetidine compounds, compositions containing them and their use in methods of treating or preventing disorders or diseases associated with AT2 receptor function including neuropathic pain, inflammatory pain, conditions associated with neuronal hypersensitivity, impaired nerve conduction velocity, cell proliferation disorders, disorders associated with an imbalance between bone resorption and bone formation and disorders associated with aberrant nerve regeneration.
- -
-
-
- Syngas-mediated C-C bond formation in flow: Selective rhodium-catalysed hydroformylation of styrenes
-
We report a continuous flow, rhodium-catalysed hydroformylation of various styrenes using a tube-in-tube gas-liquid reactor. The flow process afforded selectively branched aryl aldehydes in good yields. Georg Thieme Verlag Stuttgart · New York.
- Kasinathan, Sivarajan,Bourne, Samuel L.,Tolstoy, P?ivi,Koos, Peter,Obrien, Matthew,Bates, Roderick W.,Baxendale, Ian R.,Ley, Steven V.
-
scheme or table
p. 2648 - 2651
(2011/12/04)
-
- Synthesis, complexation behavior and application of a new diphosphite ligand in rhodium-catalyzed hydroformylation
-
Oxidative coupling of 3-(3-tert-butyl-4-hydroxyphenyl)propionic acid methyl ester (2) gave dimethyl 3,3′-(5,5′-di-tert-butyl-6,6′- dihydroxybiphenyl-3,3′-diyl)-dipropionate (1c), which upon phosphorylation/transesterification with a phosphochloridite derived from (R)-binaphthol, formed the new unsymmetrical binaphthol-bridged diphosphite 4. A rhodium catalyst based on 4 as ligand gave predominantly iso-selectivity in the hydroformylation of selected styrenes but opposite regioselectivity with 2,6-disubstituted derivatives. New chelate metal complexes (acac)RhL, PdCl 2L and PtCl2L have been synthesized by reacting 4 with (acac)Rh(CO)2, PdCl2(MeCN)2 and PtCl 2(COD), respectively. The structure of obtained compounds is determined based on 1H, 13C, 31P and 195Pt NMR spectroscopy and mass spectrometry data.
- Mikhel, Igor S.,Dubrovina, Natalia V.,Shuklov, Ivan A.,Baumann, Wolfgang,Selent, Detlef,Jiao, Haijun,Christiansen, Andrea,Franke, Robert,Boerner, Armin
-
experimental part
p. 3050 - 3057
(2011/09/20)
-
- Double arylation of allyl alcohol via a one-pot heck arylation- isomerization-acylation cascade
-
A one-pot, two-step catalytic protocol has been developed. A regioselective Heck coupling between aryl bromides and allyl alcohol leads to the generation of arylated allyl alcohols that in situ isomerize to give aldehydes, which then undergo an acylation reaction with a second aryl bromide. A variety of aryl bromides can be employed in both the initial Heck reaction and the acylation, providing easy access to a wide variety of substituted dihydrochalcones.
- Colbon, Paul,Ruan, Jiwu,Purdie, Mark,Mulholland, Keith,Xiao, Jianliang
-
supporting information; experimental part
p. 5456 - 5459
(2011/12/05)
-
- Design of a series of bicyclic HIV-1 integrase inhibitors. Part 2: Azoles: Effective metal chelators
-
Synthesis of a diverse set of azoles and their utilizations as an amide isostere in the design of HIV integrase inhibitors is described. The Letter identified thiazole, oxazole, and imidazole as the most promising heterocycles. Initial SAR studies indicat
- Le, Giang,Vandegraaff, Nick,Rhodes, David I.,Jones, Eric D.,Coates, Jonathan A.V.,Thienthong, Neeranat,Winfield, Lisa J.,Lu, Long,Li, Xinming,Yu, Changjiang,Feng, Xiao,Deadman, John J.
-
scheme or table
p. 5909 - 5912
(2010/11/18)
-
- IMIDAZOPYRIMIDINONES AND USES THEREOF
-
The present invention provides a compound of formula (I) or a pharmaceutically acceptable derivative, salt or prodrug thereof. The present invention further provides a method of treatment or prophylaxis of a viral infection in a subject comprising administering to said subject an effective amount of a compound of formula (I) or a pharmaceutically acceptable derivative, salt or prodrug thereof. Pharmaceutical compositions comprising a compound of formula (I) are also provided.
- -
-
Page/Page column 80
(2010/04/03)
-
- Synthesis and application of modular phosphine-phosphoramidite ligands in asymmetric hydroformylation: Structure-selectivity relationship
-
A series of hybrid phos- phine-phosphoramidite ligands has been designed and synthesized in moderate yields from chiral BINOL (1, 1′- bi-2-naphthol) or NOBIN (2-amino-2′- hydroxy-1, 1′-binaphthyl). They have achieved highly regio- and enantiose- lectivities in Rh-catalyzed asymmetric hydroformylations of styrene derivatives (branched/linear ratio up to 56.6, ee up to 99%), vinyl acetate derivatives (up to 98% ee), and allyl cyanide (up to 96 % ee). Systematic variation of ligand structure showed that the steric factor on the phsophoramidite moiety determined the performance of the ligand. With the increased hindrance, the branched/linear ratio rose, while the ee value dropped in the hydrofor- mylation of styrene. However, the N- substituents did not influence the selec- tivities much.
- Zhang, Xiaowei,Cao, Bonan,Yan, Yongjun,Yu, Shichao,Ji, Baoming,Zhang, Xumu
-
experimental part
p. 871 - 877
(2010/06/20)
-
- Highly regioselective hydroformylation of Styrene and its derivatives catalyzed by Rh complex with tetraphosphorus ligands
-
Styrene has been hydroformylated to the linear aldehyde with surprisingly high regioselectivity (l/b up to 22 for styrene) by using Rh complex with tetraphosphorus ligand. To the best of our knowledge, this is the highest linear regioselectivity reported for the hydroformylation of styrene and its derivatives. This protocol is in sharp contrast to other processes that favor producing branched aldehyde (typically >95% branched for most bidentate systems).
- Yu, Shichao,Chie, Yu-Ming,Guan, Zheng-Hui,Zou, Yaping,Li, Wei,Zhang, Xumu
-
supporting information; experimental part
p. 241 - 244
(2009/06/28)
-
- Synthesis and antiviral activity of 7-benzyl-4-hydroxy-1,5-naphthyridin- 2(1H)-one HIV integrase inhibitors
-
The medicinal chemistry and structure-activity relationships for a novel series of 7-benzyl-4-hydroxy-1,5-naphthyridin-2(1H)-one HIV-integrase inhibitors are disclosed. Substituent effects were evaluated at the N-1, C-3, and 7-benzyl positions of the naph
- Boros, Eric E.,Edwards, Cynthia E.,Foster, Scott A.,Fuji, Masahiro,Fujiwara, Tamio,Garvey, Edward P.,Golden, Pamela L.,Hazen, Richard J.,Jeffrey, Jerry L.,Johns, Brian A.,Kawasuji, Takashi,Kiyama, Ryuichi,Koble, Cecilia S.,Kurose, Noriyuki,Miller, Wayne H.,Mote, Angela L.,Murai, Hitoshi,Sato, Akihiko,Thompson, James B.,Woodward, Mark C.,Yoshinaga, Tomokazu
-
experimental part
p. 2754 - 2761
(2010/01/16)
-
- Modular chiral bidentate phosphonites: Design, synthesis, and application in catalytic asymmetric hydroformylation reactions
-
A new class of C2-symmetric chiral bidentate phosphonite ligands has been synthesized in moderate to good yields from readily available starting materials. Application of these air-stable chiral phosphonites in the Rh I-catalyzed asymmetric hydroformylation of styrene derivatives, vinyl acetate, and allyl cyanide afforded the corresponding chiral aldehydes with high regio- and enantioselectivities under mild reaction conditions. The modular nature of the ligands allows fine-tuning of the selectivities through judicious modifications of the substituents on the ligand backbone. X-ray structural analysis of the catalyst precursor suggested that the steric hindrance caused by the protruding remote substituents of the ligands into the vicinity of the metal center might be an important factor for the enantio-control of the reaction, whereas the sense of asymmetric induction can be rationalized on the basis of a trigonal-bipyramidal transition state diagram.
- Zhao, Baoguo,Peng, Xingao,Wang, Zheng,Xia, Chungu,Ding, Kuiling
-
experimental part
p. 7847 - 7857
(2009/11/30)
-
- Highly enantioselective hydroformylation of aryl alkenes with diazaphospholane ligands
-
(Chemical Equation Presented) Asymmetric, rhodium-catalyzed hydroformylation of terminal and internal aryl alkenes with diazaphospholane ligands is reported. Under partially optimized reaction conditions, high enantioselectivity (>90% ee) and regioselectivities (up to 65:1 α:β) are obtained for most substrates. For terminal alkenes, both enantioselectivity and regioselectivity are proportional to the carbon monoxide partial pressure, but independent of hydrogen pressure. Hydroformylation of para-substituted styrene derivatives gives the highest regioselectivity for substrates bearing electron-withdrawing substituents. A Hammett analysis produces a positive linear correlation for regioselectivity.
- Watkins, Avery L.,Hashiguchi, Brian G.,Landis, Clark R.
-
scheme or table
p. 4553 - 4556
(2009/05/13)
-
- Highly selective hydroformylation of vinylarenes to branched aldehydes by [Rh(cod)Cl]2 entrapped in ionic liquid modified silica sol-gel
-
A co-entrapped mixture of [Rh(cod)Cl]2 and Na[Ph 2P-3-(C6H4SO3)] within a silica sol-gel matrix modified with ca. 5% of 1-butyl-3-[3-(trimethoxysilyl)propyl] imidazolium chloride catalyzes, in n-heptane, the hydroformylation of a variety of vinylarenes. At 50°C and under 6.9 bar each of H2 and CO the reaction is high-yielding and highly selective. Non-hindered substrates give >95 % of branched aldehydes and only 5% of the linear isomers. The ceramic catalyst is leach-proof and recyclable. It does not lose its high catalytic activity and selectivity for at least four runs. The selectivity depends on the pressure of the gases, the temperature and the solvent. The electronic nature has no influence on the selectivity, but the latter is diminished by steric effects. Upon omission of the sol-gel component, the catalyst deteriorates and practically loses its activity after the first half-life of the reaction. In the absence of the ionic liquid, the catalyst undergoes substantial leaching. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Hamza, Khalil,Blum, Jochanan
-
p. 4706 - 4710
(2008/03/13)
-
- HIV INTEGRASE INHIBITORS
-
The present infention features compounds that are HIV integrase inhibitors and may be useful in the inhibition of HIV replication, the prevention and/or treatment of infection by HIV, and in the treatment of AIDS and/or ARC.
- -
-
Page/Page column 36
(2008/06/13)
-
- Conjugate reduction of α,β-unsaturated aldehydes with rhodium(bis-oxazolinylphenyl) catalysts
-
α,β-Unsaturated aldehydes were selectively reduced using rhodium(bisoxazolinylphenyl) complexes to give exclusive 1,4-selectivity in the combination of alkoxyhydrosilanes. Georg Thieme Verlag Stuttgart.
- Kanazawa, Yoshinori,Nishiyama, Hisao
-
p. 3343 - 3345
(2008/09/18)
-
- NAPHTHYLIDINE DERIVATIVE HAVING HIV INTEGRASE INHIBITORY ACTIVITY
-
[Problems to be Solved] To provide a novel compound having antiviral activity, especially inhibitory activity against HIV integrase, a pharmaceutical composition, especially anti-HIV drug, containing the same. [Means to Solve the Problem] A compound of th
- -
-
Page/Page column 17
(2008/06/13)
-
- Biocatalytic racemization of (hetero)aryl-aliphatic α- hydroxycarboxylic acids by Lactobacillus spp. proceeds via an oxidation-reduction sequence
-
The biocatalytic racemization of a range of (hetero)aryl- and (di)aryl-aliphatic α-hydroxycarboxylic acids has been achieved by using whole resting cells of Lactobacillus spp. The essentially mild (physiological) reaction conditions ensure the suppression of undesired side reactions, such as elimination, decomposition or condensation. Cofactor/inhibitor studies using a cell-free extract of Lactobacillus paracasei DSM 20207 reveal that the addition of redox cofactors (NAD+/NADH) leads to a distinct increase in the racemization rate, while strong inhibition is observed in the presence of Thio-NAD+, which suggests that the racemization proceeds by an oxidation-reduction sequence rather than involvement of a "racemase" enzyme. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Nestl, Bettina M.,Glueck, Silvia M.,Hall, Melanie,Kroutil, Wolfgang,Stuermer, Rainer,Hauer, Bernhard,Faber, Kurt
-
p. 4573 - 4577
(2007/10/03)
-
- A hybrid phosphorus ligand for highly enantioselective asymmetric hydroformylation
-
A new hybrid phosphorus ligand has been prepared starting from chiral NOBIN (2-amino-2-hydroxy-1,1-binaphthyl). Excellent enantioselectivities (up to 99% ee) have been achieved in the Rh-catalyzed asymmetric hydroformylations of styrene derivatives and vinyl acetate.
- Yan, Yongjun,Zhang, Xumu
-
p. 7198 - 7202
(2007/10/03)
-
- N-UREIDOALKYL-AMINO COMPOUNDS AS MODULATORS OF CHEMOKINE RECEPTOR ACTIVITY
-
The present application describes modulators of chemokine receptors of formula (I), or pharmaceutically acceptable salt forms thereof, useful for the prevention of asthma and other allergic diseases.
- -
-
-